The F5 BIG-IP appliance must require that when a password is changed, the characters are changed in at least eight of the positions within the password.

If the application allows the user to consecutively reuse extensive portions of passwords, this increases the chances of password compromise by increasing the window of opportunity for attempts at guessing and brute-force attacks.

The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different.

Multifactor authentication (MFA) is required for all administrative and user accounts on network devices, except for an account of last resort and (where applicable) a root account. Passwords must only be used when MFA using PKI is not available, and for the account of last resort and root account.

From the BIG-IP console, type the following command:

tmsh list sys db password.difok

Note: Verify the value is set to at least 8.

If the BIG-IP appliance is not configured to require that when a password is changed, the characters are changed in at least eight of the positions within the password, this is a finding.

If this setting has been changed from the default value of 8, reset the value.

From the BIG-IP console, type the following command:

tmsh modify sys db password.difok value 8 tmsh save sys config